Multiplying and Dividing Exponents/Transcript
Transcript Onscreen text reads: The Mysteries of Life with Tim & Moby Tim and Moby are in their living room. Tim is reading the newspaper. Moby is at the living room table, making a paper plane. TIM: I heard there might be an earthquake sometime soon. Moby panics and ducks under the table, holding pillows on his head. Tim laughs. TIM: You big coward. MOBY: Beep. Tim reads from a typed letter. TIM: Dear Tim and Moby, We're multiplying and dividing powers, and I am so lost. Can you help? From, Jack. I had trouble with that, too. Until Moby straightened me out. MOBY: Beep. TIM: Seeing 10 to the power of 2 can, well, it can freak you out. But 10² is just 10 × 10, and 10 × 10 = 100. Text shows 10². Additional text reads: 10 × 10. Additional text reads: 100. TIM: So, say we want to multiply 10² and 10³. On a sheet of newspaper, Moby writes the equation Tim describes. TIM: Powers that have the same base can be multiplied by adding their exponents. 10 to the power of 5 is 100,000. Text shows the number 10 with exponents 2 and 3 added together to make 10 with an exponent of 5. Additional text reads: 100,000. TIM: Let's check our math. We've already determined that 10² = 100. 10³ is 10 × 10 × 10. That's 1,000. 100 times 1,000 is 100,000. Text shows the equations and figures Tim describes. MOBY: Beep. TIM: Hey, where's that Richter scale we made? MOBY: Beep. Moby digs a Richter scale chart from a crack in the living room sofa. TIM: The intensity of an earthquake is measured on something called the Richter scale. These numbers represent earthquake intensities in powers of 10. An image shows a Richter scale chart. It displays the numbers 1 to 12. Each number is assigned a value of 10 to a power. The 1 on the Richter scale corresponds to 10º. The2 on the Richter scale is 10¹. The 3 on the Richter scale is 10². And so on. TIM: It's a little confusing, so pay attention. Remember that any number to the power of 0 equals 1, right? So, on the Richter scale, 10 to the power of 0 has an intensity of 1. 10 to the power of 1 has an intensity of 2. And so on. Tim uses a pointer to draw attention to relevant text on the Richter scale chart as he explains it. TIM: That's why the Richter scale number is always one less than the exponent. MOBY: Beep. TIM: You got it. An earthquake that registers 8 on the Richter scale has an intensity of 10 to the power of 7. So, how many times more intense is an earthquake that measures 8 on the Richter scale than an earthquake that measures 5? We can find out by dividing. You divide powers that have the same base by subtracting their exponents. You've got 10 to the power of 7, minus 4, which equals 3. 10 to the power of 3 is 1,000. On a sheet of newspaper, Moby writes the equations and figures that Tim describes. TIM: So that Richter 8 earthquake is 1,000 times more intense than the Richter 5 earthquake. Nice work, Moby. There is a sudden rumbling sound. MOBY: Beep. Tim hides under the table, holding pillows on his head as Moby did earlier. Through the living room window, a jet plane can be seen flying by. The plane is causing the rumbling sound. Moby looks beneath the table at Tim. MOBY: Beep. TIM: Oh, be quiet. Category:BrainPOP Transcripts Category:BrainPOP Math Transcripts